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From: sashiko-bot@kernel.org
Subject: Re: [PATCH 1/2] rust: pci: add domain_nr() accessor
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To: "John Hubbard" <jhubbard@nvidia.com>, "Danilo Krummrich" <dakr@kernel.org>, "Alexandre
 Courbot" <acourbot@nvidia.com>
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 Courtney" <ecourtney@nvidia.com>, "Zhi Wang" <zhiw@nvidia.com>, "David
 Airlie" <airlied@gmail.com>, "Simona Vetter" <simona@ffwll.ch>, "Bjorn
 Helgaas" <bhelgaas@google.com>, "Miguel Ojeda" <ojeda@kernel.org>, "Boqun
 Feng" <boqun@kernel.org>, "Gary Guo" <gary@garyguo.net>, =?utf-8?b?Qmo=?=
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 Gross" <tmgross@umich.edu>, nova-gpu@lists.linux.dev, dri-devel@lists.freedesktop.org, linux-pci@vger.kernel.org
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 <20261110033655.148487-2-jhubbard@nvidia.com>
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Date: Tue, 10 Nov 2026 03:48:31 +0000
Precedence: list

Thank you for your contribution! Sashiko AI review found 1 potential
issue to consider:
- [Medium] rust: pci: signature mismatch in rust_helper_pci_domain_nr()
  on ppc and s390
--

commit 40ebd2410b826b9813de5dae1bbe6075723a08bc
Author: John Hubbard <jhubbard@nvidia.com>

rust: pci: add domain_nr() accessor

This commit adds a domain_nr() accessor to pci::Device and a corresponding
rust_helper_pci_domain_nr() C helper to retrieve the PCI domain number.

> diff --git a/rust/helpers/pci.c b/rust/helpers/pci.c
> index a8540f90b13ce..49f2c089d2369 100644
> --- a/rust/helpers/pci.c
> +++ b/rust/helpers/pci.c
> @@ -7,6 +7,11 @@ __rust_helper u16 rust_helper_pci_dev_id(struct pci_dev =
*dev)
>  	return PCI_DEVID(dev->bus->number, dev->devfn);
>  }
> =20
> +__rust_helper int rust_helper_pci_domain_nr(struct pci_dev *dev)
> +{
> +	return pci_domain_nr(dev->bus);
> +}
> +
>  __rust_helper resource_size_t
>  rust_helper_pci_resource_start(struct pci_dev *pdev, int bar)
>  {
> diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs
> index 769d01d234296..57718e48208d5 100644
> --- a/rust/kernel/pci.rs
> +++ b/rust/kernel/pci.rs
> @@ -408,6 +408,20 @@ pub fn dev_id(&self) -> u16 {
>          unsafe { bindings::pci_dev_id(self.as_raw()) }
>      }
> =20
> +    /// Returns the PCI domain number of the bus that this device is on.
> +    #[inline]
> +    pub fn domain_nr(&self) -> u32 {
> +        // SAFETY: By its type invariant `self.as_raw` is always a valid=
 pointer to a
> +        // `struct pci_dev`.
> +        let domain_nr =3D unsafe { bindings::pci_domain_nr(self.as_raw()=
) };

[Severity: Medium]
Does bindings::pci_domain_nr(self.as_raw()) fail to compile on PowerPC and
s390 due to a pointer type mismatch?

In rust/bindings/lib.rs, bindings_generated.rs is included after
pub use super::bindings_helper::*, so any non-inline C function emitted by
bindgen shadows a rust_helper_* wrapper of the same stripped name.  On Powe=
rPC
(arch/powerpc/include/asm/pci.h) and s390 (arch/s390/include/asm/pci.h),
pci_domain_nr() is declared as a non-inline extern function taking
struct pci_bus * rather than a static inline function:

arch/powerpc/include/asm/pci.h:
extern int pci_domain_nr(struct pci_bus *bus);

On those architectures, bindings::pci_domain_nr resolves to the C declarati=
on
expecting *mut bindings::pci_bus instead of the helper's
*mut bindings::pci_dev, breaking the build when CONFIG_RUST and CONFIG_PCI =
are
enabled.  Either rust_helper_pci_domain_nr() should take struct pci_bus *bu=
s to
match the C signature (with domain_nr() passing (*self.as_raw()).bus), or t=
he
helper should use a distinct name that does not collide with C pci_domain_n=
r().

--=20
Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261110033655.1484=
87-1-jhubbard@nvidia.com?part=3D1